exchanges: Refactor time handling and other minor improvements (#1948)

* exchanges: Refactor time handling and other minor improvements

- Updated Kraken wrapper to utilise new time handling methods.
- Simplified Kucoin types by removing unnecessary structures and using direct JSON unmarshalling.
- Improved websocket handling in Kucoin to directly parse candlestick data.
- Modified Lbank types to use the new time representation.
- Adjusted Poloniex wrapper and types to utilise the new time handling.
- Updated Yobit types and wrapper to reflect changes in time representation.
- Introduced DateTime type for better handling of specific time formats.
- Added tests for DateTime unmarshalling to ensure correctness.
- Rid UTC().Unix and UTC().UnixMilli as it's not needed
- Correct Huobi timestamp usage for some endpoints.
- Rid RFC3339 time parsing since Go does that automatically.

* exchanges: Refactor JSON unmarshalling for various types and improve test coverage

* linter: Update error message in TestGetKlines

* refactor: Simplify JSON unmarshalling in MovementHistory and improve test assertions in GetKlines

* refactor: Improve JSON unmarshalling for channel name and clarify comment in wsProcessOpenOrders

* refactor: Update time handling in Huobi types to use types.Time for createdAt fields and relax GetLiquidationOrders test

* refactor: Move wsTicker, wsSpread, wsTrades, and wsCandle types to kraken_types.go for better organistion

* refactor: Add validation for underlying parameter in GetExpirationTime and update tests

exchanges/bitstamp/bitstamp_wrapper.go

@@ -264,7 +264,7 @@ func (b *Bitstamp) UpdateTicker(ctx context.Context, p currency.Pair, a asset.It
 		Volume:       tick.Volume,
 		Open:         tick.Open,
 		Pair:         fPair,
-		LastUpdated:  time.Unix(tick.Timestamp, 0),
+		LastUpdated:  tick.Timestamp.Time(),
 		ExchangeName: b.Name,
 		AssetType:    a,
 	})
@@ -386,15 +386,10 @@ func (b *Bitstamp) GetWithdrawalsHistory(ctx context.Context, c currency.Code, _
 	}
 	resp := make([]exchange.WithdrawalHistory, 0, len(withdrawals))
 	for i := range withdrawals {
-		var tm time.Time
-		tm, err = parseTime(withdrawals[i].Date)
-		if err != nil {
-			return nil, fmt.Errorf("getWithdrawalsHistory unable to parse Date field: %w", err)
-		}
 		if c.IsEmpty() || c.Equal(withdrawals[i].Currency) {
 			resp = append(resp, exchange.WithdrawalHistory{
 				Status:          strconv.FormatInt(withdrawals[i].Status, 10),
-				Timestamp:       tm,
+				Timestamp:       withdrawals[i].Date.Time(),
 				Currency:        withdrawals[i].Currency.String(),
 				Amount:          withdrawals[i].Amount,
 				TransferType:    strconv.FormatInt(withdrawals[i].Type, 10),
@@ -432,7 +427,7 @@ func (b *Bitstamp) GetRecentTrades(ctx context.Context, p currency.Pair, assetTy
 			Side:         s,
 			Price:        tradeData[i].Price,
 			Amount:       tradeData[i].Amount,
-			Timestamp:    time.Unix(tradeData[i].Date, 0),
+			Timestamp:    tradeData[i].Date.Time(),
 		}
 	}
 
@@ -531,10 +526,6 @@ func (b *Bitstamp) GetOrderInfo(ctx context.Context, orderID string, _ currency.
 			Amount: o.Transactions[i].ToCurrency,
 		}
 	}
-	orderDate, err := time.Parse(time.DateTime, o.DateTime)
-	if err != nil {
-		return nil, err
-	}
 	status, err := order.StringToOrderStatus(o.Status)
 	if err != nil {
 		return nil, err
@@ -542,7 +533,7 @@ func (b *Bitstamp) GetOrderInfo(ctx context.Context, orderID string, _ currency.
 	return &order.Detail{
 		RemainingAmount: o.AmountRemaining,
 		OrderID:         o.ID,
-		Date:            orderDate,
+		Date:            o.DateTime.Time(),
 		Trades:          th,
 		Status:          status,
 	}, nil
@@ -677,13 +668,6 @@ func (b *Bitstamp) GetActiveOrders(ctx context.Context, req *order.MultiOrderReq
 			orderSide = order.Sell
 		}
 
-		var tm time.Time
-		tm, err = parseTime(resp[i].DateTime)
-		if err != nil {
-			log.Errorf(log.ExchangeSys,
-				"%s GetActiveOrders unable to parse time: %s\n", b.Name, err)
-		}
-
 		var p currency.Pair
 		if currPair == "all" {
 			// Currency pairs are returned as format "currency_pair": "BTC/USD"
@@ -702,7 +686,7 @@ func (b *Bitstamp) GetActiveOrders(ctx context.Context, req *order.MultiOrderReq
 			Price:    resp[i].Price,
 			Type:     order.Limit,
 			Side:     orderSide,
-			Date:     tm,
+			Date:     resp[i].DateTime.Time(),
 			Pair:     p,
 			Exchange: b.Name,
 		}
@@ -776,16 +760,9 @@ func (b *Bitstamp) GetOrderHistory(ctx context.Context, req *order.MultiOrderReq
 				format.Delimiter)
 		}
 
-		var tm time.Time
-		tm, err = parseTime(resp[i].Date)
-		if err != nil {
-			log.Errorf(log.ExchangeSys,
-				"%s GetOrderHistory unable to parse time: %s\n", b.Name, err)
-		}
-
 		orders = append(orders, order.Detail{
 			OrderID:  strconv.FormatInt(resp[i].OrderID, 10),
-			Date:     tm,
+			Date:     resp[i].Date.Time(),
 			Exchange: b.Name,
 			Pair:     currPair,
 		})